Wrist-type body component measuring apparatus and body component measuring method using the same

ABSTRACT

The wrist-type body component measuring apparatus includes: a band configured to be worn on a wrist of a user; a first input electrode and a first output electrode disposed on an inside surface of the band and configured to be in contact with the wrist of the user; a second input electrode and a second output electrode disposed on an outside surface of the band; a measuring unit configured to apply a current to the first and second input electrodes and detect a voltage from the first and second output electrodes to measure a body impedance of the user; and an electrode converter configured to convert a disposition of the first and second input electrodes and the first and second output electrodes based on a determination of whether the band is worn on a left wrist or a right wrist of the user.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/804,718, filed on Jul. 21, 2015, in the U.S. Patent and TrademarkOffice, which claims priority from Korean Patent Application No.10-2014-0154732, filed on Nov. 7, 2014, in the Korean IntellectualProperty Office, the disclosures of which are incorporated herein intheir entireties by reference.

BACKGROUND 1. Field

Apparatuses and methods consistent with exemplary embodiments relate tobody component measuring apparatuses and methods.

2. Description of the Related Art

Interest in healthcare has increased with the development of medicalscience and the recent extension of the average life span of humanbeings. In this regard, interest in medical instruments has alsoincreased. The range of this interest has extended not only to variousmedical instruments used in test organizations, but also to small andmedium-sized medical instruments equipped in public institutions,small-sized medical instruments possessed or carried by individualpersons, and healthcare apparatuses.

A body component measuring apparatus is a kind of healthcare apparatus.The body component measuring apparatus measures a body component byusing a bioelectrical impedance analysis (BIA) method that analyzes abody component by accurately measuring a body impedance depending on thequantity of a body component such as water, protein, bone, or fatincluded in a human body. The BIA method regards a human body as acombination of impedances, flows a current through the human body,measures a voltage caused by the current, and measures an impedance ofthe human body from the current and the voltage.

SUMMARY

One or more exemplary embodiments provide body component measuringapparatuses and methods.

According to an aspect of an exemplary embodiment, there is provided awrist-type body component measuring apparatus including: a bandconfigured to be worn by a user; a first input electrode and a firstoutput electrode disposed on an inside surface of the band andconfigured to be in contact with a wrist of a user; a second inputelectrode and a second output electrode disposed on an outside surfaceof the band; a measuring unit configured to apply a current to the firstand second input electrodes and detect a voltage from the first andsecond output electrodes to measure a body impedance of the user; and anelectrode converter configured to convert a disposition of the first andsecond input electrodes and the first and second output electrodes basedon a whether the band is worn on a left wrist or a right wrist of theuser.

The measuring unit may include: a current provider configured to applythe current to the first and second input electrodes; a voltage detectorconfigured to detect the voltage from the first and second outputelectrodes; and an impedance calculator configured to calculate the bodyimpedance from the current and the voltage.

The electrode converter may include a plurality of switches configuredto convert terminals of the first and second output electrodes and thefirst and second input electrodes connected to both terminals of thevoltage detector and the current provider.

An arrangement direction of the first input electrode and the firstoutput electrode and an arrangement direction of the second inputelectrode and the second output electrode may be different from alengthwise direction of the band.

The arrangement direction of the first input electrode and the firstoutput electrode and the arrangement direction of the second inputelectrode and the second output electrode may be perpendicular to thelengthwise direction of the band.

The wrist-type body component measuring apparatus may further include asensor configured to determine whether the band is worn on the leftwrist or the right wrist. The electrode disposition is converted suchthat the first input electrode and the second input electrode aredisposed on a hand side and the first output electrode and the secondoutput electrode are disposed on a body side based on the determination.

The wrist-type body component measuring apparatus may further include asensor disposed to face a radial artery of the user and configured tosense whether the band is worn on the left wrist or on the right wristby using a biometric signal received from the radial artery.

The sensor may include a light sensor configured to detect anelectrocardiography (ECG) signal, a galvanic skin reflex (GSR) signal, aphotoplethysmography (PPG) signal, or a pulse wave.

The wrist-type body component measuring apparatus may further include aplurality of sensors arranged in a direction perpendicular to alengthwise direction of the band with a predetermined distancetherebetween, and configured to sense whether the band is worn on theleft wrist or on the right wrist by using a signal received according toa movement of the user.

The sensors may include acceleration sensors.

The wrist-type body component measuring apparatus may further include aninput unit configured to input information about whether the band isworn on the left wrist or on the right wrist.

A body component of the user may be analyzed from the body impedancemeasured by the measuring unit, and the body component may include atleast one of body fat, body water, skeletal muscle mass, protein,mineral, visceral fat, body cell mass, bone mineral content, musclestrength, and edema.

The wrist-type body component measuring apparatus may include a memoryconfigured to store an impedance of an end body part of the user that isto be in contact with the second input electrode and the second outputelectrode, for body impedance measurement.

According to an aspect of another exemplary embodiment, there isprovided a wrist-type body component measuring apparatus including: aband configured to be worn on a wrist of a user; a first input electrodeand a first output electrode disposed on an inside surface of theapparatus to be in contact with the wrist of the user; a second inputelectrode and a second output electrode disposed on an outside surfaceof the apparatus; a measuring unit configured to apply a current to thefirst and second input electrodes and detect a voltage from the firstand second output electrodes to measure a body impedance of the user; amemory configured to store a first measurement value in response to theband being worn on a left wrist or a right wrist of the user; and anelectrode converter configured to compare the first measurement valuestored in the memory and a second measurement value measured by themeasurement unit and convert a disposition of the first and second inputelectrodes and the first and second output electrodes according towhether the apparatus is worn on the left wrist or the right wrist.

The measuring unit may include: a current provider configured to applythe current to the first and second input electrodes; a voltage detectorconfigured to detect the voltage from the first and second outputelectrodes; and an impedance calculator configured to calculate theimpedance of the user from the current and the voltage.

The electrode converter may include a plurality of switches configuredto convert terminals of the first and second output electrodes and thefirst and second input electrodes connected to both terminals of thevoltage detector and the current provider.

An arrangement direction of the first input electrode and the firstoutput electrode and an arrangement direction of the second inputelectrode and the second output electrode may be different from alengthwise direction of the band.

The arrangement direction of the first input electrode and the firstoutput electrode and the arrangement direction of the second inputelectrode and the second output electrode may be perpendicular to thelengthwise direction of the band.

According to whether the apparatus is worn on the left wrist or on theright wrist, the electrode disposition may be converted such that thefirst input electrode and the second input electrode are disposed on ahand side and the first output electrode and the second output electrodeare disposed on a body side.

A body component of the user may be analyzed from the body impedancemeasured by the measuring unit, and the body component may include atleast one of body fat, body water, muscle strength, and edema.

The memory may store an impedance of an end body part of the user thatis to be in contact with the second input electrode and the secondoutput electrode, for body impedance measurement.

According to an aspect of another exemplary embodiment, there is providea method of measuring a body component of a user by a wrist-type bodycomponent measuring apparatus including first and second inputelectrodes and first and second output electrodes. The method mayinclude: determining whether the first and second input electrodes aredisposed farther from the center of the body of the user than the firstand second output electrodes; providing a current between the firstinput electrode and the second input electrode; measuring a voltagebetween the first output electrode and the second output electrode; anddetermining a body impedance of the user based on the measured voltage.

The body component measuring method may further include converting anelectrode disposition of the first and second input electrodes and thefirst and second output electrodes in response to the first and secondinput electrodes being disposed farther from the center of the body thanof the first and second output electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will be more apparent by describingcertain exemplary embodiments, with reference to the accompanyingdrawings, in which:

FIGS. 1A and 1B are perspective views of a wrist-type body componentmeasuring apparatus according to an exemplary embodiment, whichillustrate an outside surface and an inside surface of a straprespectively;

FIG. 2 illustrates an example of a body component measurement postureusing the wrist-type body component measuring apparatus according to anexemplary embodiment;

FIG. 3A is a block diagram illustrating a schematic configuration of thewrist-type body component measuring apparatus according to an exemplaryembodiment;

FIG. 3B is a block diagram illustrating an exemplary configuration of ameasuring unit included in the wrist-type body component measuringapparatus;

FIG. 4A illustrates a schematic circuit diagram for body impedancemeasurement in the body component measurement posture illustrated inFIG. 2 ;

FIG. 4B illustrates an equivalent circuit diagram for body impedancemeasurement;

FIG. 4C is a graph illustrating a body impedance change depending on anelectrode disposition and an end body part contacting an electrode unit;

FIG. 5 is a perspective view of a wrist and a biometric signalprocessing apparatus for detecting biometric signals by using aplurality of sensors according to an exemplary embodiment;

FIG. 6 is a graph illustrating signal waveforms of biometric signalsmeasured by the biometric signal processing apparatus;

FIG. 7 is a diagram exemplarily illustrating an end portion of an armwhen an object rotates the arm;

FIG. 8 illustrates a plurality of electrode units and a circuit diagramconnected thereto according to an exemplary embodiment;

FIGS. 9A and 9B illustrate a plurality of electrode units, which havechanged in relative positions, and a circuit diagram connected theretoaccording to an exemplary embodiment; and

FIG. 10 is a flowchart schematically illustrating a body componentmeasuring method according to an exemplary embodiment.

DETAILED DESCRIPTION

Exemplary embodiments are described in greater detail below withreference to the accompanying drawings.

In the following description, like drawing reference numerals are usedfor like elements, even in different drawings. The matters defined inthe description, such as detailed construction and elements, areprovided to assist in a comprehensive understanding of the exemplaryembodiments. However, it is apparent that the exemplary embodiments canbe practiced without those specifically defined matters. Also,well-known functions or constructions are not described in detail sincethey would obscure the description with unnecessary detail. As usedherein, expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

It will be understood that when a layer is referred to as being “on”another layer or substrate, it may be directly on the other layer orsubstrate, or one or more intervening layers may also be present.

Although terms such as “first” and “second” may be used herein todescribe various elements or components, these elements or componentsshould not be limited by these terms. These terms are only used todistinguish one element or component from another element or component.

As used herein, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will also be understood that the terms “comprises”,“includes”, and “has”, when used herein, specify the presence of statedelements, but do not preclude the presence or addition of otherelements, unless otherwise defined.

FIGS. 1A and 1B are perspective views of a wrist-type body componentmeasuring apparatus 100 according to an exemplary embodiment, whichillustrate an outside surface and an inside surface of a straprespectively. FIG. 2 illustrates an example of a body componentmeasurement posture using the wrist-type body component measuringapparatus 100 according to an exemplary embodiment.

Referring to FIGS. 1A, 1B, and 2 , the wrist-type body componentmeasuring apparatus 100 includes a band that is wearable on a wrist of auser and includes a main body MB and a strap ST. Two straps ST areprovided on both sides of the main body MB such that they are connectedto the main body MB to be worn on a wrist of an object. A first inputelectrode 110 and a first output electrode 115 are formed on an insidesurface STb of one of the two straps ST, and a second input electrode120 and a second output electrode 125 are formed on an outside surfaceSTa thereof.

The first input electrode 110 and the first output electrode 115 arebrought into contact with the wrist of the object when the wrist-typebody component measuring apparatus 100 is worn on a user that is theobject whose body component is to be measured.

The second input electrode 120 and the second output electrode 125 arebrought into contact with an end body part of the other wrist on whichthe wrist-type body component measuring apparatus 100 is not worn. Theend body part of the other wrist, which may contact the second inputelectrode 120 and the second output electrode 125, is not limited to aspecific region. For example, a finger, a plurality of fingers, a palm,the back of the hand, or the side of the hand may contact the secondinput electrode 120 and the second output electrode 125. Formeasurement, as illustrated in FIG. 2 , a finger may contact the secondinput electrode 120 and the second output electrode 125 simultaneously,or different fingers may contact the second input electrode 120 and thesecond output electrode 125, respectively.

FIGS. 1A and 1B illustrate that the first input electrode 110 and thefirst output electrode 115 are disposed on one side of the strap STopposite to another side of the strap ST on which the second inputelectrode 120 and the second output electrode 125 are respectivelydisposed. However, this is merely exemplary, and the first inputelectrode 110 and the first output electrode 115 may not be accuratelyopposite to the second input electrode 120 and the second outputelectrode 125.

The first input electrode 110 and the first output electrode 115 may bedisposed on the inside surface STb of the strap ST or an inside surfaceof the main body MB to directly contact the object when the object wearsthe wrist-type body component measuring apparatus 100, and the secondinput electrode 120 and the second output electrode 125 may be disposedon the outside surface STa of the strap ST or an outside surface of themain body MB. In this case, the first input electrode 110 and the firstoutput electrode 115 disposed on the inside surface STb of the strap STor the inside surface of the main body MB and the second input electrode120 and the second output electrode 125 disposed on the outside surfaceSTa of the strap ST or the outside surface of the main body MB may bearranged in a direction non-parallel to a lengthwise direction of thestrap ST. For example, as illustrated in FIGS. 1A, 1B, and 2 , the firstinput electrode 110 and the first output electrode 115 may be disposedon the inside surface STb of the strap ST, the second input electrode120 and the second output electrode 125 may be disposed on the outsidesurface STa of the strap ST. Further, the first input electrode 110, andthe first output electrode 115 may be arranged in a directionperpendicular to the lengthwise direction of the strap ST each other,and the second input electrode 120 and the second output electrode 125may be arranged in the same direction each other. The first inputelectrode 110, the first output electrode 115, the second inputelectrode 120, and the second output electrode 125 may form a closedcircuit passing through both arms. The length of the path of the closedcircuit may be measured to obtain a body impedance. For example, a bodyimpedance may be measured by detecting the length of a path of a closedcircuit including two pairs of electrodes, one of which is disposedfarther from the center of the body than the other pair of electrodes. Adetailed method of measuring the body impedance by using a plurality ofelectrodes and a relative disposition relationship of the first inputelectrode 110, the first output electrode 115, the second inputelectrode 120, and the second output electrode 125 will be describedlater with reference to FIGS. 3A, 3B, and 4.

FIG. 3A is a block diagram illustrating a schematic configuration of thewrist-type body component measuring apparatus 100 according to anexemplary embodiment. FIG. 3B is a block diagram illustrating anexemplary configuration of a measuring unit 140 included in thewrist-type body component measuring apparatus 100. FIG. 4A illustrates aschematic circuit diagram for body impedance measurement in the bodycomponent measurement posture illustrated in FIG. 2 . FIG. 4Billustrates an equivalent circuit diagram for body impedance measurementin the body component measurement posture illustrated in FIG. 2 . FIG.4C is a graph illustrating a body impedance change depending on anelectrode disposition and an end body part contacting an electrode unit.

Referring to FIGS. 3A and 3B, the measuring unit 140 applies a currentto the first input electrode 110 and the second input electrode 120 anddetects a voltage from the first output electrode 115 and the secondoutput electrode 125 to measure a body impedance of the object.

The measuring unit 140 may include a current provider 142 configured toapply a current to the first input electrode 110 and the second inputelectrode 120, a voltage detector 144 configured to detect a voltagebetween the first output electrode 115 and the second output electrode125, and an impedance calculator 146 configured to calculate a bodyimpedance of the object by using the applied current and the detectedvoltage. The voltage detector 144 may include an operational amplifierconfigured to amplify a voltage between the first output electrode 115and the second output electrode 125, and a filter configured to remove anoise.

The body impedance measured by the measuring unit 140 may be used by ananalyzer to analyze a body component of the object. The analyzer may bestored in the form of a program in a memory 160, and may be executed bya processor 155.

The processor 155 may be hardware that controls the overall function andoperation of the wrist-type body component measuring apparatus 100. Theprocessor 155 may analyze the body component by using the body impedancemeasured by the measuring unit 140 by executing the program stored inthe memory 160. Herein, the body component may include body fat, skincharacteristics (e.g., body water), muscle strength, or edema of theobject.

For example, in addition to analyzing the body component from the bodyimpedance, the processor 155 may control the measuring unit 140 tomeasure the body impedance and may process image signals to display thebody component analysis results.

The processor 155 may be implemented in the form of a microprocessormodule or in the form of a combination of two or more microprocessormodules. That is, the processor 155 may be implemented in various forms.

The memory 160 may store a program for operation of the wrist-type bodycomponent measuring apparatus 100 and data necessary for this. Thememory 160 may include general storage mediums such as a hard disk drive(HDD), a read-only memory (ROM), a random-access memory (RAM), a flashmemory, and a memory card.

The memory 160 may store a program for correcting the body impedancemeasured by the measuring unit 140 and a program for analyzing the bodycomponent from the corrected body impedance. Also, the memory 160 maystore additional data such as height, weight, and sex. Also, the memory160 may store an impedance of each end body part of the object, such as,for example, an impedance of a finger, which is necessary for bodyimpedance correction.

A user interface 170 may receive an input for operating the wrist-typebody component measuring apparatus 100 from the object, and may outputinformation about the body component of the object processed by theprocessor 155. The user interface 170 may include an input unit 171configured to allow the object to operate the wrist-type body componentmeasuring apparatus 100, and an output unit 172 configured to output theresults of the wrist-type body component measuring apparatus 100.

The input unit 171 of the user interface 170 may include a button, akeypad, a switch, a dial, or a touch interface that allows the object tooperate the wrist-type body component measuring apparatus 100. Theoutput unit 172 of the user interface 170 may include a displayconfigured to display an image, and may be implemented by a touchscreen.The display may include a display panel such as a liquid crystal display(LCD) panel or an organic light-emitting display (OLED) panel, and maydisplay information about the body component analysis results in theform of an image or a text. Also, the user interface 170 may include aninput/output (I/O) port for connecting a human interface device (HID),and may include an I/O port for inputting/outputting an image.

The object may input additional data, such as the wear position of thewrist-type body component measuring apparatus 100 and the height,weight, and sex of the object, through the input unit 171 of the userinterface 170, and may obtain information about the body componentmeasurement results through the output unit 172 of the user interface170.

Although FIGS. 1A, 1B, and 3A illustrate that the first input electrode110, the second input electrode 120, the first output electrode 115, andthe second output electrode 125 are disposed in the strap ST and themeasuring unit 140, the processor 155, the memory 160, and the userinterface 170 are disposed in the main body MB, exemplary embodimentsare not limited thereto. The first input electrode 110, the second inputelectrode 120, the first output electrode 115, and the second outputelectrode 125 may also be disposed in a divided manner on a frontsurface and a rear surface of the main body MB to contact the wrist ofthe object and the end body part of the other wrist on which thewrist-type body component measuring apparatus 100 is not worn. Also, inthe wrist-type body component measuring apparatus 100, the first inputelectrode 110, the second input electrode 120, the first outputelectrode 115, the second output electrode 125, the measuring unit 140,the processor 155, the memory 160, and the user interface 170 may bemodularized and disposed in the main body MB or the strap ST.

Referring to FIGS. 2, 4A, and 4B, the wrist-type body componentmeasuring apparatus 100 may be worn on the left wrist of the object, anda right-hand index finger f1 may be brought into contact with the secondinput electrode 120 and the second output electrode 125.

In the equivalent impedance of the object, the impedances of the rightarm, the body, and the left arm may form a body impedance Z_(body), andthe impedance of the right-hand index finger f1 used for measurement isZ_(f1). Since the right-hand index finger f1 contacts the second inputelectrode 120 and the second output electrode 125 simultaneously, animpedance calculated from a voltage measured through the first outputelectrode 115 and the second output electrode 125 is Z_(body)+Z_(f1) asillustrated in FIGS. 4A and 4B. The impedance (Z_(body)+Z_(f1)) minusthe impedance Z_(f1) of the right-hand index finger f1 is the bodyimpedance Z_(body). The impedance Z_(f1) of the right-hand index fingerf1 may be pre-measured and stored in the memory 160.

The object may use fingers other than the index finger, such as the bigfinger, the middle finger, and the ring finger, for measurement. Also inthis case, the body impedance may be calculated by correcting themeasured impedance from the prestored values such as the big-fingerimpedance and the middle-finger impedance. As described above, in orderto measure the body impedance Z_(body), a pair of input electrodes 110and 120 and a pair of output electrodes 115 and 125 are disposed in adivided manner on the inside surface STb and the outside surface STa ofthe wrist-type body component measuring apparatus 100. In an exemplaryembodiment, the body impedance Z_(body) is measured by separatelycalculating and correcting a finger impedance Z_(f); however, exemplaryembodiments are not limited thereto. The total impedance including thefinger impedance may be measured. When two or more fingers are broughtinto contact with electrodes spaced apart from each other with the twoor more fingers separated from each other, the body impedance Z_(body)excluding the influence of the finger impedance Z_(f) may be directlymeasured.

FIG. 4C is a graph illustrating a body impedance Z_(body) variation inthe case where the pair of input electrodes 110 and 120 are disposed onthe hand side and in the case where the pair of input electrodes 110 and120 are disposed on the body side. Referring to FIG. 4C, when the pairof input electrodes 110 and 120 are disposed on the hand side than whenthe pair of input electrodes 110 and 120 are disposed on the body side,a variation of the body impedance Z_(body), which is measured accordingto the contact of the end body part (e.g., the index finger, the middlefinger, the ring finger, or the index/middle fingers) of the other wriston which the wrist-type body component measuring apparatus 100 is notworn, is reduced and thus more stable measurement values may beobtained. That is, stable measurement values may be obtained bymeasuring a voltage on a current path, through which a constant currentflows, with a measurement target therebetween. Thus, the pair of inputelectrodes 110 and 120 may be disposed on the hand side of the object,and the pair of output electrodes 115 and 125 may be disposed on thebody side of the object.

As an example, the wrist-type body component measuring apparatus 100 maybe worn on the left or right wrist of the object, and the disposition ofthe pair of input electrodes 110 and 120 and the pair of outputelectrodes 115 and 125 may be converted according to the wrist on whichthe wrist-type body component measuring apparatus 100 is worn. Forexample, referring to FIGS. 1A, 1B, and 2 , when the wrist-type bodycomponent measuring apparatus 100 is worn on the left wrist, the pair ofinput electrodes 110 and 120 are disposed on the body side of the objectand the pair of output electrodes 115 and 125 are disposed on the handside of the object. On the other hand, when the wrist-type bodycomponent measuring apparatus 100 is worn on the right wrist, the pairof input electrodes 110 and 120 are disposed on the hand side of theobject and the pair of output electrodes 115 and 125 are disposed on thehand body side of the object. Thus, when the wrist on which thewrist-type body component measuring apparatus 100 is worn is determined,a more stable body impedance Z_(body) value may be obtained by adjustingthe disposition positions of the plurality of electrodes according to onwhich wrist, right or left, the wrist-type body component measuringapparatus 100 is worn.

According to an exemplary embodiment, in order to determine the wrist onwhich the wrist-type body component measuring apparatus 100 is worn, theobject may use the input unit 171 of the user interface 170 to inputinformation indicating on which wrist, right or left, the wrist-typebody component measuring apparatus 100 is worn.

According to another exemplary embodiment, on which wrist the wrist-typebody component measuring apparatus 100 is worn may be determined byusing the body impedance Z_(body) value measured by using the pluralityof electrodes. Referring to FIGS. 2 and 4C, a variation of the bodyimpedance Z_(body) value in the case where the wrist-type body componentmeasuring apparatus 100 is worn on the left wrist and the pair of inputelectrodes 110 and 120 and the pair of output electrodes 115 and 125 aredisposed on the hand side or the body side may be detected. In thisregard, a case where the wrist-type body component measuring apparatus100 is worn on the left wrist, the pair of input electrodes 110 and 120are disposed on the hand side, and the pair of output electrodes 115 and125 are disposed on the body side is set by default, and a firstmeasurement value measured in this case, for example, a variation of afirst body impedance Z_(body) is stored in the memory 160. When thewrist-type body component measuring apparatus 100 having the sameelectrode disposition is worn on the object, a second measurement value,for example, a second body impedance Z_(body) is measured, and avariation equal to a variation of the body impedance Z_(body) valueinput to the memory 160 is measured, it may be determined that thewrist-type body component measuring apparatus 100 is worn on the leftwrist. On the other hand, a variation larger than a measurement valueinput to the memory 160, for example, a variation of the body impedanceZ_(body) is measured, it may be determined that the wrist-type bodycomponent measuring apparatus 100 is worn on the right wrist.

According to another exemplary embodiment, in order to determine thewrist on which the wrist-type body component measuring apparatus 100 isworn, a sensor may be used to sense the wrist on which the wrist-typebody component measuring apparatus 100 is worn.

FIG. 5 is a perspective view of a wrist and a biometric signalprocessing apparatus 300 for detecting biometric signals by using aplurality of sensors according to an exemplary embodiment. FIG. 6 is agraph illustrating signal waveforms of biometric signals measured by thebiometric signal processing apparatus 300.

Referring to FIG. 5 , the biometric signal processing apparatus 300includes a plurality of light sensors 311 and 312 configured to radiatelight in a contact or noncontact manner onto a skin surface above aradial artery 350, and a processor configured to process signals sensedfrom the light sensors 311 and 312. The light sensors 311 and 312 detectbiometric signals of the object, such as an electrocardiography (ECG)signal, a galvanic skin reflex (GSR) signal, a photoplethysmography(PPG) signal, and a pulse wave. The light sensors 311 and 312 may detectbiometric signals of the object by using signals reflected by radiatinglight to the object; however, exemplary embodiments are not limitedthereto. Also, the light sensors 311 and 312 may detect biometricsignals of the object by using electrical signals, magnetic signals, orpressures.

As an example, in order to measure an arterial blood pressure, thebiometric signal processing apparatus 300 may detect a PPG signal byradiating light to the radial artery 350. When a PPG signal is detectedfrom a skin surface of the wrist through which the radial artery 350passes, the influence of external factors causing a detection error,such as the thickness of a skin tissue in the wrist, may be smallest.Also, it is known that the radial artery 350 is a blood vessel fromwhich a more accurate PPG signal may be detected than from other typesof blood vessels in the wrist. However, a blood vessel to which thebiometric signal processing apparatus 300 may be applied is not limitedto the radial artery 350, and a PPG signal may be detected from bloodvessels of other regions of the wrist, other than the radial artery 350.Also, although a method of detecting the biometric signal byphotoelectric conversion is described in an exemplary embodiment,exemplary embodiments are not limited thereto and the biometric signalmay also be detected by piezoelectric conversion, mechanical conversion,magnetic conversion, or the like.

The first light sensor 311 and the second light sensor 312 may bedisposed on the inside surface STb of the strap ST or the main body MBwith a predetermined distance therebetween, and may be arranged in adirection perpendicular to the lengthwise direction of the strap ST anddisposed to face the radial artery 350. Since the first light sensor 311and the second light sensor 312 are spaced apart from each other by apredetermined distance, similar biometric signals, for example, arterialblood pressures may be measured with a predetermined time differencetherebetween. Referring to FIG. 6 , a time-dependent first signalwaveform S of the arterial blood pressure of the first light sensor 311and a time-dependent second signal waveform P of the arterial bloodpressure of the second light sensor 312 are illustrated. It may be seenthat the first signal waveform S and the second signal waveform P aremeasured in similar forms and the phase of the first signal waveform Sprecedes the phase of the second signal waveform P. From the phasedifference between the signal waveforms, it may be determined that abloodstream flows from the first light sensor 311 to the second lightsensor 312. Thus, when the phase of the first signal waveform S precedesthe phase of the second signal waveform P in the wrist-type bodycomponent measuring apparatus 100 illustrated in FIG. 5 , it may bedetermined that the wrist-type body component measuring apparatus 100 isworn on the left wrist. When the phase of the second signal waveform Pprecedes the phase of the first signal waveform S, it may be determinedthat the wrist-type body component measuring apparatus 100 is worn onthe right wrist.

FIG. 7 is a diagram exemplarily illustrating an acceleration change ofan end portion of an arm when the object rotates the arm.

The object may rotate the arm with the wrist-type body componentmeasuring apparatus 100 worn thereon. In this case, an accelerationmeasuring apparatus including a plurality of acceleration sensors may beused to determine on which wrist, right or left, the wrist-type bodycomponent measuring apparatus 100 is worn.

Referring to FIG. 7 , an acceleration measuring apparatus 400 includes aplurality of acceleration sensors 411 and 412 configured to sense anacceleration component generated when the object rotates the arm, and aprocessor configured to process signals sensed from the accelerationsensors 411 and 412. The acceleration sensors 411 and 412 may measureacceleration components of one or more of an X axis and a Y axis. Whenthe object rotates the arm at an angular speed ω, an X-axis accelerationcomponent a_(x) and a Y-axis acceleration component a_(y) may beexpressed as below.a_(x)=rω², a_(y)=r

The first acceleration sensor 411 and the second acceleration sensor 412may be disposed on the inside surface STb of the strap ST or the mainbody MB of the wrist-type body component measuring apparatus 100 with apredetermined distance therebetween, and may be arranged in a directionperpendicular to the lengthwise direction of the strap ST. Since thefirst acceleration sensor 411 and the second acceleration sensor 412 arespaced apart from each other by a predetermined distance, their rotationradiuses on the elbow or shoulder of the object are different from eachother. Thus, an X-axis acceleration component a_(x1) and a Y-axisacceleration component a_(y1) of the first acceleration sensor 411having a first rotation radius r₁ and an X-axis acceleration componenta_(x2) and a Y-axis acceleration component a_(y2) of the secondacceleration sensor 412 having a second rotation radius r₂ may beexpressed as below.a_(x1)=r₁ω², a_(y1)=r₁

a_(x2)=r₂ω², a_(y2)=r₂

In this case, since the first acceleration sensor 411 and the secondacceleration sensor 412 are disposed on the same rotation track, anangular speed ω of the first acceleration sensor 411 and an angularacceleration.

of the second acceleration sensor 412 are equal to each other.

In the wrist-type body component measuring apparatus 100 illustrated inFIG. 7 , when the X-axis acceleration component a_(x2) or the Y-axisacceleration component a_(y2) of the second acceleration sensor 412 isgreater than the X-axis acceleration component a_(x1) or the Y-axisacceleration component a_(y1) of the first acceleration sensor 411, thesecond rotation radius r₂ of the second acceleration sensor 412 isgreater than the first rotation radius r₁ of the first accelerationsensor 411. Thus, it may be determined that the wrist-type bodycomponent measuring apparatus 100 is worn on the right wrist.

When the X-axis acceleration component a_(x2) or the Y-axis accelerationcomponent a_(y2) of the second acceleration sensor 412 is smaller thanthe X-axis acceleration component a_(x1) or the Y-axis accelerationcomponent a_(y1) of the first acceleration sensor 411, the secondrotation radius r₂ of the second acceleration sensor 412 is smaller thanthe first rotation radius r₁ of the first acceleration sensor 411. Thus,it may be determined that the wrist-type body component measuringapparatus 100 is worn on the left wrist.

As described above, the input unit 171 of the user interface 170 or thesensor may be used to determine on which wrist, right or left, thewrist-type body component measuring apparatus 100 is worn. The relativepositions of the plurality of electrodes may be changed according to onwhich wrist, right or left, the wrist-type body component measuringapparatus 100 is worn. Therefore, in order to measure a body impedancehaving a small change value depending on the measurement positions, therelative positions of the plurality of electrodes should also be changedaccording to on which wrist, right or left, the wrist-type bodycomponent measuring apparatus 100 is worn.

FIG. 8 illustrates a plurality of electrode units and a circuit diagramconnected thereto according to an exemplary embodiment. FIGS. 9A and 9Billustrate a plurality of electrode units, which have changed inrelative positions, and a circuit diagram connected thereto according toan exemplary embodiment.

Referring to FIGS. 1A, 1B, and 8 , a first electrode 111 and a secondelectrode 116 are disposed on the inside surface STb of the strap ST,and a third electrode 126 and a fourth electrode 121 are disposed on theoutside surface STa of the strap ST. In this case, the first electrode111 and the fourth electrode 121 are a pair of current electrodes thatare disposed on the hand side of the object and connected to bothterminals of the current provider 142. The second electrode 116 and thethird electrode 126 are a pair of voltage electrodes that are disposedon the body side of the object and connected to both terminals of thevoltage detector 144. The first, second, third, and fourth electrodes111, 116, 126, and 121 are connected to fixed terminals of a circuitunit by first, second, third, and fourth switches 131, 132, 133, and134.

The object may change the side type of the wrist on which the wrist-typebody component measuring apparatus 100 is worn. For example, when thewrist on which the wrist-type body component measuring apparatus 100 isworn changes from the left wrist to the right wrist, the first electrode111 and the fourth electrode 121 are disposed on the body side of theobject and the second electrode 116 and the third electrode 126 aredisposed on the hand side of the object. In this case, when the firstelectrode 111 and the fourth electrode 121 are a pair of currentelectrodes and the second electrode 116 and the third electrode 126 area pair of voltage electrodes, the pair of current electrodes aredisposed on the body side of the object and the pair of voltageelectrodes are disposed on the hand side of the object, so that a bodyimpedance having a relatively large variation may be measured. In thiscase, when the first electrode 111 and the fourth electrode 121 areconverted into the pair of voltage electrodes and the second electrode116 and the third electrode 126 are converted into the pair of currentelectrodes, a body impedance having a relatively small variation may bemeasured.

As an example, switches may be used as an electrode converter thatconverts the disposition of the pair of current electrodes and the pairof the voltage electrodes. For example, referring to FIG. 9A accordingto an exemplary embodiment, the connections of the first switch 131 andthe second switch 132 are changed such that the first switch 131connected to the first electrode 111 is connected to one terminal of thevoltage detector 144 and the second switch 132 connected to the secondelectrode 116 is connected to one terminal of the current provider 142.Also, the connections of the third switch 133 and the fourth switch 134are changed such that the third switch 133 connected to the thirdelectrode 126 is connected to one terminal of the current provider 142and the fourth switch 134 connected to the fourth electrode 121 isconnected to one terminal of the voltage detector 144. Accordingly, thesecond electrode 116 and the third electrode 126 may be connected toboth terminals of the current provider 142, and the first electrode 111and the fourth electrode 121 may be connected to both terminals of thevoltage detector 144. Thus, even when the wrist on which the wrist-typebody component measuring apparatus 100 is worn changes from the leftwrist to the right wrist, the pair of current electrodes (i.e., thesecond electrode 116 and the third electrode 126) connected to bothterminals of the current provider 142 may be disposed on the hand sideand the pair of voltage electrodes (i.e., the first electrode 111 andthe fourth electrode 121) connected to both terminals of the voltagedetector 144 may be disposed on the body side.

As another example, an additional circuit configuration may be used toconvert the disposition of the pair of current electrodes and the pairof the voltage electrodes. For example, referring to FIG. 9B accordingto an exemplary embodiment, an additional circuit diagram is connectedto both terminals of the voltage detector 144, and an additional circuitdiagram is connected to both terminals of the current provider 142. Theconnections of the first switch 131 and the second switch 132 arechanged such that the first switch 131 connected to the first electrode111 is connected to one terminal of the voltage detector 144 of theadditional circuit diagram and the second switch 132 connected to thesecond electrode 116 is connected to one terminal of the currentprovider 142 of the additional circuit diagram. Also, the connections ofthe third switch 133 and the fourth switch 134 are changed such that thethird switch 133 connected to the third electrode 126 is connected toone terminal of the current provider 142 of the additional circuitdiagram and the fourth switch 134 connected to the fourth electrode 121is connected to one terminal of the voltage detector 144 of theadditional circuit diagram. Accordingly, the second electrode 116 andthe third electrode 126 may be connected to both terminals of thecurrent provider 142, and the first electrode 111 and the fourthelectrode 121 may be connected to both terminals of the voltage detector144. Thus, even when the wrist on which the wrist-type body componentmeasuring apparatus 100 is worn changes from the left wrist to the rightwrist, the pair of current electrodes (i.e., the second electrode 116and the third electrode 126) connected to both terminals of the currentprovider 142 may be disposed on the hand side and the pair of voltageelectrodes (i.e., the first electrode 111 and the fourth electrode 121)connected to both terminals of the voltage detector 144 may be disposedon the body side. However, exemplary embodiments are not limitedthereto, and an electrical configuration or a structural modificationmay also be used to change the disposition of the pair of voltageelectrodes and the pair of the current electrodes according to on whichwrist, right or left, the wrist-type body component measuring apparatus100 is worn.

FIG. 10 is a flowchart schematically illustrating a body componentmeasuring method according to an exemplary embodiment.

Information about a wrist wearing the wrist-type body componentmeasuring apparatus 100. The information may indicate which wrist, leftor right, a user is wearing the apparatus 100. The information may beinput by the user or sensed by the sensor (operation S210).

According to on which wrist, right or left, the wrist-type bodycomponent measuring apparatus 100 is worn, it is determined whether apair of input electrodes are disposed on the hand side and a pair ofoutput electrodes are disposed on the body side (operation S211). Thehand side and the body side mean positions relative to each other.Specifically, the hand side may refer to a position which is fartherfrom the center of the body than the body side.

When the pair of input electrodes are disposed on the body side and thepair of output electrodes are disposed on the hand side, the electrodedisposition is converted by switches (operation S212).

When the pair of input electrodes are disposed on the hand side and thepair of output electrodes are disposed on the body side, a relevant bodypart is brought into contact with the second input electrode and thesecond output electrode (operation S215).

The measuring unit provides a current between the first and second inputelectrodes and measures a voltage between the first and second outputelectrodes (operation S220).

An impedance is calculated from the provided current and the measuredvoltage (operation S225). The calculated impedance may be Z_(a)+Z_(body)or Z_(body) as illustrated above. Z_(a) is an impedance of a contactedend body part a.

A body component is analyzed from the calculated body impedance(operation S235).

The body component analysis results are output in the form of an imageor a text (operation S240).

For impedance correction (operation S230), the impedance of the end bodypart which is used for measurement may be pre-measured and stored.

As described above, according to the one or more of the above exemplaryembodiments, the wrist-type body component measuring apparatus maymeasure the body component of the object by measuring the impedance ofthe object with relatively high accuracy.

Also, since the electrode disposition may be converted by sensing themode of wearing the wrist-type body component measuring apparatus on theobject, the wear freedom degree of the wrist-type body componentmeasuring apparatus is high and thus the convenience of the object maybe increased.

While not restricted thereto, an exemplary embodiment can be embodied ascomputer-readable code on a computer-readable recording medium. Thecomputer-readable recording medium is any data storage device that canstore data that can be thereafter read by a computer system. Examples ofthe computer-readable recording medium include read-only memory (ROM),random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, andoptical data storage devices. The computer-readable recording medium canalso be distributed over network-coupled computer systems so that thecomputer-readable code is stored and executed in a distributed fashion.Also, an exemplary embodiment may be written as a computer programtransmitted over a computer-readable transmission medium, such as acarrier wave, and received and implemented in general-use orspecial-purpose digital computers that execute the programs. Moreover,it is understood that in exemplary embodiments, one or more units of theabove-described apparatuses and devices can include circuitry, aprocessor, a microprocessor, etc., and may execute a computer programstored in a computer-readable medium.

The foregoing exemplary embodiments are merely exemplary and are not tobe construed as limiting. The present disclosure can be readily appliedto other types of apparatuses. Also, the description of the exemplaryembodiments is intended to be illustrative, and not to limit the scopeof the claims, and many alternatives, modifications, and variations willbe apparent to those skilled in the art.

What is claimed is:
 1. A method of measuring a body component of a userby a body component measuring apparatus including a band configured tobe worn on the user, a first input electrode and a first outputelectrode which are disposed on an inside surface of the band andconfigured to contact a wrist of the user, a second input electrode anda second output electrode which are disposed on an outside surface ofthe band, a measuring circuit configured to apply a current to the firstand second input electrodes and detect a voltage from the first andsecond output electrodes to measure a body impedance of the user, and aninput interface that comprises at least one of a button, a keypad, and atouch display, and configured to receive, from the user, informationabout whether the band is worn on a left wrist or a right wrist of theuser, the method comprising: receiving, from the user, the informationabout whether the band is worn on the left wrist or the right wrist ofthe user; determining whether the first input electrode disposed on theinside surface of the band and the second input electrode disposed onthe outside surface of the band are disposed farther from a center of abody of the user than the first output electrode disposed on the insidesurface of the band and the second output electrode disposed on theoutside surface of the band; converting a disposition of the first andsecond input electrodes and the first and second output electrodesaccording to the information about whether the band is worn on the leftwrist or the right wrist; providing the current between the first inputelectrode and the second input electrode; measuring the voltage betweenthe first output electrode and the second output electrode; anddetermining the body impedance of the user based on the measuredvoltage.
 2. The method of claim 1, wherein the body component measuringapparatus further comprises an electrode converter configured to convertthe disposition of the first and second input electrodes and the firstand second output electrodes, wherein the measuring circuit comprises: acurrent source circuit configured to apply the current to the first andsecond input electrodes; a voltmeter configured to detect the voltagefrom the first and second output electrodes; and an impedancecalculating circuit configured to calculate the body impedance from thecurrent and the voltage, and wherein the electrode converter comprises aplurality of switches configured to change a first connection betweeneach of the first and second output electrodes and the voltmeter and asecond connection between each of the first and second input electrodesand the current source circuit to a third connection between each of thefirst and second output electrodes and the current source circuit and afourth connection between each of the first and second input electrodesand the voltmeter.
 3. The method of claim 1, wherein an arrangementdirection of the first input electrode and the first output electrodeand an arrangement direction of the second input electrode and thesecond output electrode are different from a lengthwise direction of theband.
 4. The method of claim 3, wherein the arrangement direction of thefirst input electrode and the first output electrode and the arrangementdirection of the second input electrode and the second output electrodeare perpendicular to the lengthwise direction of the band.